National income refers to the total monetary value of all goods and services produced within a country over a specific period, usually a year. It includes various components such as wages, profits, rents, and taxes, minus subsidies. National income is an important indicator of a country's economic health and helps in comparing economic performance over time or between different countries. Economists often measure national income using methods like the Gross Domestic Product (GDP) or Net National Product (NNP). These measurements provide insights into the standard of living, economic growth, and overall productivity of a nation, guiding policymakers in making informed decisions.